Methods of determining interferon having direct inhibitory effects on tumors and uses thereof

Abstract

The invention provides novel methods of determining or comparing potency of a test interferon relative to rSIFN-co (an interferon having therapeutic effects on solid tumors); methods of establishing substantial equivalence between a test interferon and rSIFN-co; as well as methods for determining potency of a test interferon, kits for determination of such methods, and an interferon or an interferon substitute having said activities.

What is claimed: 
     
       1. A method of determining or comparing potency of a test interferon relative to Recombinant Super-Compound Interferon (rSIFN-co), or establishing substantial equivalence between a test interferon and rSIFN-co, comprising the steps of:
 (1) providing a first sample, a second sample and a third sample of cancer cells of the same type; 
 (2) treating the first sample with the test interferon, treating the second sample with rSIFN-co, and using the third sample as a control sample; and 
 (3) measuring binding affinity of said test interferon and rSIFN-co to Interferon Alpha And Beta Receptor Subunit 1 (IFNAR1) and Interferon Alpha And Beta Receptor Subunit 2 (IFNAR2) in the first, second and third samples; 
 wherein similar binding affinity to IFNAR1 between the first and second samples, and similar binding affinity to IFNAR2 between the first and second sample indicates substantial equivalence between the test interferon and the rSIFN-co. 
 
     
     
       2. The method of  claim 1 , wherein the cancer cells comprise any one or more of: lung cancer cells, colon cancer cells, cervical cancer cells, liver cancer cells, breast cancer cells, and pancreatic cancer cells. 
     
     
       3. The method of  claim 1 , wherein the cancer cells comprise HT-29 cells. 
     
     
       4. The method of  claim 1 , wherein the test interferon has about 2, 3, 4, or 4.5 times higher binding affinity to IFNAR1 as compared to the third sample containing IFNα-2b. 
     
     
       5. The method of  claim 1 , wherein the test interferon has about 5, 7, 9, or 11 times lower binding affinity to IFNAR2 as compared to the third sample containing IFNα-2b. 
     
     
       6. The method of  claim 1 , wherein the binding affinity to IFNAR1 or IFNAR2 is determined by dissociation constant (K D ). 
     
     
       7. The method of  claim 1 , wherein the test interferon has an amino acid sequence that is at least 90% identical to SEQ ID NO: 1. 
     
     
       8. The method of  claim 1 , wherein the test interferon is encoded by a nucleotide sequence that is at least 90% identical to SEQ ID NO: 2. 
     
     
       9. The method of  claim 1 , wherein the test interferon and rSIFN-co have the same amino acid sequence of SEQ ID NO: 1, and are encoded by the same nucleotide sequence of SEQ ID NO: 2. 
     
     
       10. The method of  claim 1 , wherein the test interferon and rSIFN-co have substantially the same specific activity. 
     
     
       11. The method of  claim 10 , wherein the specific activity is in the range between about 4×10 8  IU/mg and about 1×10 9  IU/mg.